1. Field of the Invention
This invention relates particularly to the strip material used to form well screen structures.
2. Description of the Prior Art
It is not an uncommon practice in the prior art to form well screens by winding a strip about supporting rods to form a substantially cylindrical screen. However, in the prior art practice, it is apparent that the strip material used is formed of a uniform material and a wire core is also known to be used.
In U.S. Letters Patent No. 1,858,592 it is disclosed that a ribbon is wound about supporting rods with no description being given of the substance of the ribbon. In U.S. Letters Patent No. 4,068,713 there is disclosed the use of a PVC strip wound about a core. In U.S. Pat. No. 3,385,373 there is disclosed the use of a strip of plastic having a metal wire core to be wound about supporting rods. In U.S. Pat. No. 3,864,182 there is shown the use of a high density polyethylene.
In U.S. Pat. No. 3,709,293 a wedge shaped wire is shown wrapped about supporting rods but the substance of the wire is not defined. In U.S. Pat. No. 3,658,128 there is defined a strip formed of bundles of glass filaments embodied in a resin forming the outer surface of a well screen.
The invention herein makes a disclosure with respect to the use of a dual durometer strip material of two or more dissimilar material which is particularly adapted to withstand handling and installation of stresses to provide a long useful life.